This invention relates generally to a method of mounting of electronic component mounts formed on FPC tape carriers.
It is the practice in the manufacture and assembly of electronic apparatus, such as circuit boards or circuit display panels, to feed a series of electronic component mounts to a mounting apparatus for the purpose of mounting or otherwise mechanically and/or electrically securing the electronic component mounts to the apparatus. These electronic component mounts are formed spatially along the length of a tape carrier and are generally wound on a reel after electronic components, such as semiconductor integrated circuit chips, have been mounted relative to printed circuit lead patterns provided on the tape carrier. Then, the reel of component mounts is transferred to a mounting apparatus wherein the component mounts are separated from the tape carrier and mounted relative to the electronic apparatus being assembled. More recently, FPC tape carriers have been developed to provide for securing, such as by gang bonding, of integrated circuit chips to preformed printed circuit lead patterns spatially provided along the length of tile tape carrier. In some cases, these tapes have now been de facto standardized to the size of 35 mm photographic film.
An example of such a tape carrier is shown in FIG. 13 comprising tape carrier I having a series of sprocket holes 1B along each edge of the carrier between which are spatially formed electronic component mounts 2 each comprising an electronic device or semiconductor integrated circuit chip 2' having electrical connections or output pads gang bonded to the inner ends of one or more lead patterns 2", which lead patterns have been previously formed directly onto tape carrier 1. Tape carrier 1 may be made of polyimide film or the like. Sprocket holes 1B as well as holes in carrier 1 at the position of chip 2' are formed by a punch press. After these holes are formed in carrier 1, a thin metal film or leaf, such as a laminate copper leaf, is formed along the surface of the tape over the holes formed for chips 2'. Thereafter, photolithography is performed employing a photoresist to pattern and selectively etch the film to form lead patterns 2".
There may also be an opening 2A provided in the film adjacent to the outer ends of the lead pattern 2" to provide a series of lead portions overhanging opening 2A forming a mounting region 2"' when electronic component mounts 2 are removed or separated from tape carrier film 1 by means of cutting or severing along a cut out boundary 4.
In the past, it has been the practice to separate electronic component mounts 2 from tape carrier I primer to their assembly relative to electronic apparatus. Thus, the first step is to remove all electronic components 2 from a single tape carrier 1. Since electronic component mounts 2 are physically separated from tape carrier 1, hereinafter referred to as their out-of-tape state, they are autonomic relative one another and relative to carrier tape 1. In this out-of-tape state, component mounts 2 will, of course, have no predetermined alignment relative to one another as they did in their in-tape state. Therefore, they must be transferred as a plural group, properly aligned and positioned for their final assembly relative to mechanical and electrical connection to electronic apparatus being assembled. Thus, the removal of component mounts 2 from carrier tape 1 prior to assemblage relative to such electronic apparatus renders it difficult to consider and successfully improvise a continuously automated process from the electronic component in-tape state to their out-of-tape state, such as in the case wherein the individual electronic component mounts 2 are assembled into electronic apparatus by means, for example, via an outer lead bonding (OLB) process relative to the outer ends of the leads or mounting regions 2"' of lead patterns 2".
Thus, in prior component and mount assembly technology relating to the OLB process for tape carrier lead patterns 2", individual electronic component mounts 2 were separated from FPC tape 1 in their out-of-tape state rendering it difficult to automate the OLB process. Even if the OLB process was automated to handle mounts 2 previously separated from tape carrier 1, means would have to be provided for the individual handling, orientation, transport and positioning in OLB apparatus for accomplishing pressure adhesion attachment and lead connection into electronic apparatus undergoing assembly. Such means is complicated in design and operation since the out-of-tape state mounts 2 have to be individually handled and manipulated by such means prior to application of the OLB process. Thus, production efficiency is not increased with a significant advancement in automation of the overall assembly process by such an approach.
Thus, it is an object of this invention to provide a tape carrier that can be automated with the outer lead bonding (OLB) process performed from the in-tape state wherein the electronic component mounts are separated from the tape carrier and assembled via mounting apparatus into electronic apparatus undergoing assembly.
It is another object of this invention to provide minimal securing means for maintaining electronic component mounts within the confines of the body of a tape carrier but easily separated therefrom by appropriately severing the securing means for immediate mount assembly.